Without using iCloud, the iPhone, iPad, and iPod backups can take up a lot of local disk space on a computer. If you’ve moved the iPhone/iPad to sync with a new computer, sold an iOS device, or just want to potentially free up some disk space, you can easily delete these backups directly from iTunes.
  1. Launch iTunes and open iTunes Preferences
  2. Click the “Devices” tab to find the backup list
  3. Select the backup(s) you wish to delete and click “Delete Backup”
This only removes the backups that are stored locally on the computer and it will not impact iCloud backups, which won’t even show up in the list.